Polyvinyl acetal resin compositions containing diethylene glycol ditetrahydrofuroate



Patented Nov. 12, 1940 POLYVINYL ACETAL RESIN COMPOSITIONS CONTAINING DIETHYLENE GLYCOL. DI-

-'IlltTRAHYDROFUROATE v Henry B. Smith, Rochester, my,

Eastman Kodak Company, Rocheste i Y.,' a corporation or NewJerbey No Drawing. Application December 22, 1938,

- Serial No. 247,301

This invention relates to plastic compositions, and more particularly to compositions comprisin a polyvinyl acetal resin and a conditioning agent.

One object of this invention is to produce compositions of matter, which may bemade into permanently transparent, strong and flexible sheets or films of desired thinness which are substantially Waterproof, are unaffected by ordinary photographic fluids and possess the desired properties of a support for sensitive photographic coatings. Another object of my invention is toproduce compositions of matter which can be made into sheets suitable for use in laminated,- shatter-p rooi glass. Still another object is to produce compositions which can be rolled, extruded, molded or otherwise worked into relatively thick sheets ,and massive plastics. A further object is to produce compositions suitable for use in lacquers, artificial silk filaments, wrapping tissues and the like. Other objects will hereinafter appear.

I have discovered that diethylene glycol ditetrahydrofuroate is a useful conditioning agent for polyvinyl acetal resins. Not only does it serve as a proporti of the acetal groups are butyraldehyde acetal groups, it has an'unusual and remarkable 'eflect which I may call elasticiz ingfl That is to say, a sheet of polyvinyl 'butyraldehyde acetal resin containing about or, more /parts of diethylene glycol ditetrahydrofuroate per 100 parts of resin possessesthe property which, in the rubber industry, is known as nerve: namely, the

property stretching to a considerable extent when tension is exerted upon it, and returning to its original dimensions when the tension is released. This property renders such sheets, which I shall call ."rubbery sheets, particularly useful in,the manufacture of shatter-proof glass 0 For the manufacture oi cast films or sheets, the polyvinyl acetal resin and diethylene glycol ditetrahydrofuroate may be dissolved in a suitable solvent or'solvent mixture, such, for instance, as acetone, methanol, acetone-methanol ,mixtures, ethylene chloride-methanol mixtures, etc., about 300 to 500 or more parts of thesolvent or solvent mixture being used per parts of the resin. From about 5 to 100 parts or more of diethylene glycol ditetrahydroiuroate per 100 parts of resin ment.

mixture may then be .worke the manner described in U. S. Patent 2,048,686

may be employed, depending upon the nature of the resin and the purpose for which the sheets are to be used. Suitable proportions of diethylene glycol ditetrahydrofuroate for any resin and any purpose may be readily determined by experi- For' the manufacture of sheets suitable,

for photographic film base, from 5 to 25 parts of diethyleneglycol ditetrahydroiuroate per 100 parts of resin are suitable. The resin solution is.

castas a sheet, the solvent evaporated, and the sheet stripped from the casting surface;

Sheets for use in' laminated glass may be of F. R. Conklin, until complete homogenization has taken place. The mass thus produced may then be extruded through an annular die, and the tube so formed slit to form a sheet. v

The polyvinyl acetal resins can be prepared by reacting polyvinyl alcohol with an aldehydein the. presence of an acetal condensation catalyst, e. g. a mineral acid. These resins can also be prepared by simultaneously de-esterifying a polyvinyl aliphatic ester and reacting the] de-esteriflcationproduct with an aldehyde in the presence of a de-esterifying catalyst'and acetal condensation catalyst. Mineral acids are catalysts for both ric esteriflcation and acetal formation. Among the polyvinyl acetal resins with which diethylene glycol ditetrahydrofuroate is useul.may be mentioned, as illustrative examples, the polyvinyl formaldehyde acetal resins, the polyvinyl acetaldehyde acetal resins, the polyvinyl formaldehyde acetaldehyde mixed acetal resins, the polyvinyl butyraldehyde acetal resins,and the polyvinyl" butyraldehyde acetaldehyde mixed acetal resins. Examples of the preparation of polyvinyl rmaldehyde acetal resins may be found in. U. S.

, P tent 1,955,068, Examples 1, 4 and 5; in U. S.

10 C., and the on hot rolls,'in,-

in British Patent 436,072, Examples 1, 2, 3, 4, 5, 6

Examples of the preparation of polyvinyl .acetaldehyde acetal resins may be found in U.-S.

Patent 2,044,730, Example 1; U. ,s. Patent 1,955,068, Example 2; U. S. Patent 2,036,092, Ex-

amples 4, 5 and 6; British Patent 466,598, Ex-

amples 1, 2, 3, 4 and 7; British Patent 404,279,

5 Examples 1, 2, 4, 5, 6, 7 and 8; U. S. Patent 1,990,399; and French Patent 808,578, Examples 1, 2 and 3. An additional example of the preparation of a polyvinyl acetaldehyde acetal resin is poises, was dissolved 50 lbs. of 95% ethyl alcohol and 90 lbs. of ethyl.

acetate. To this solution was added 19.2 lbs. of

paraldehyde. Then a catalyst consisting of 5* lbs. of 95% sulfuric acid diluted with 5 lbs. of water was added. After thorough mixing, the reaction was allowed to proceed at 40 C. for 8.days. The reaction mixture was then diluted with acetone,

and the resin precipitated by pouring into cold water, washed and dried. Analysis showed the resin to have an acetate group content equivalent to 3.3% of polyvinyl acetate and a hydroxyl group content equivalent to 6.5% polyvinyl alcohol.

Examples-of the preparation of polyvinyl formaldehyde acetaldehyde mixed acetal resins may be found in British Patent 430,136, Examples 1, 2, 3, 4, '5 and 6; British Patent 445,565, Example 2; British Patent 465,873, Examples 1, 2, 3, 4, 5

and 6; French Patent 808,586, Examples 1, 2, 3,

4, 5, 6, 12, 13, 14, 15, 16, 17, 18 and 19. Additional examples of the preparation of polyvinyl formaldehyde acetaldehyde mixed acetal resin are as follows:

100 parts (1.16 moles calculated as monomeric vinyl acetate) of a polyvinyl acetate (45 centipoises), 100 parts of ethyl alcohol, 180 parts of ethyl acetate, 34 parts (.77 mole as monomeric acetaldehyde) of paracetaldehyde and 5.8 parts 40 (.196 mole as monomeric formaldehyde) of paraformaldehyde were placed in an enamelled vessel and brought into solution by stirring. When solution was complete, 10 parts of sulfuritVacid (sp. gr. 1.84) in 10 parts of water was added, and the mixture'stirred. The mixture was maintained at a temperature of 40 C. for 144 hours. The

contents of the vessel were then diluted with about two and a half volumes of acetone, and

the mixture precipitated by pouring into water. v The preci itated resin was washed free from impurities by repeated changes of cold water, and

dried. The resin, when analyzed, gave a hydroxyl group content equivalent to about 6.4 per cent by weight of polyvinyl alcohol, an acetate group content equivalent to about 4.0 per cent by weight of polyvinyl acetate, a formaldehyde acetal group content equivalent to about 15.9 per cent by weight of polyvinyl formaldehyde acetal and an acetaldehyde acetal group content equivalent to about 73.9 per cent by weight of polyvinyl acetaldehyde acetal. The polyvinyl acetal portion of the resin was therefore made up of about 19.7 per cent by moles of polyvinyl formaldehyde acetal and about 80.3 per cent by molesof polyvinyl 55 acetaldehyde acetal. The resin was soluble in acetone to an extent which permitted coating a film or shet from the resin.

50 parts (.58 mole as monomer) of polyvinyl acetate (45 centipoises), 50 parts of ethyl aclohol, 90 parts of ethyl acetate, 17 parts (.385 mole as monomer) of paracetaldehyde, 2.9 parts (.098 mole as monomer) of paraformaldehyde, 5 parts of sulfuric acid and 5 parts of water were treated as in Example 1 for 181 hours. The well washed 75 and dried resin gave upon analysis a hydz oxyl steam heating.

group content equivalent to about 9.6% by weight of polyvinyl alcohol, an acetate group content' equivalent to about 4.1% by weight of. polyvinyl acetate, a formaldehyde acetal group content equivalent to about 13.9 per cent by weight of polyvinyl formaldehyde acetal, and an acetaldehyde acetal group content equivalent to about 69.9 per cent of polyvinyl acetaldehyde acetal. The polyvinyl acetal portion of the resin was therefore made up of about 18.5 per cent by moles of polyvinyl formaldehyde acetal and 81.5 per cent by moles of polyvinyl acetaldehyde acetal. The resin was soluble in acetone to an extent which permitted coating a film or sheet from the resin. 7

1300 parts (15.1 mole as monomer) of a polyvinyl acetate (45 centipoises), 1700 parts. of ethyl acetate, 2250 parts of ethyl alcohol (95%) and 48 parts (1.57 moles as monomer) of paraformaldehyde (trioxymethylene) were placed in a Vessel equipped with a reflux condenser and a means of agitation; and the contents brought to'a temperature of about 70 C. by means of 182.2? parts of sulfuric acid (sp. gr. 1.84) dissolved in 5ls5 parts of water were added, and the whole was heated at about 70 C.

for about five hours, agitating throughout. At this point, 266.4 parts (6.05 mole as monomer) of paracetaldehyde were added, and heating at about 70 C. with agitation was continued for a further period of twenty hours. The contents of the reaction vessel were neutralized with ammonium hydroxide and diluted with water precipitating theresin as a cake. The cake .was cut into small pieces and repeatedly washed with hot water until the resin was free from solvents, salts and other impurities. The resin, upon analysis, showed a hydroxyl grou alent to about 10.1 per cent by eight of polyvinyl alcohol, .an acetate group content equivalent to about 3.2 per cent by weight of polyvinyl acetate, the remainder of the weight of the resin being polyvinyl acetal. The polyvinyl acetal portion of the resin was made up of about per cent by moles of polyvinyl acetaldehyde acetal and about 20 per cent by moles of polyvinyl formalde-- hyde'acet'al. The resin was not quite soluble in acetone, but could be made to dissolve by admixing small amounts of other solvents, such as alcohols, with the acetone.

Examples of the preparation of polyvinyl butyraldehyde acetal resins may be found in U. S.

Patent 2,,044,'l30,-Examples 2, 5 and 6; British Patent 466,598, Example 5; French Patent 813,303, Example 1; French Patent 813,514, Examples 1, 2, 3- and 4; and British Patent 459,878, Examples 1, 2, 5, 6, 7, 8, 9 and 10. An additional example of the preparation of a polyvinyl butyraldehyde actal resin is as follows:

20 lbs. of polyvinyl acetate, the viscosity of whose molar solution in benzene was 45 centipoises, was dissolved in 20 lbs. of 95% ethyl alcohol and 36 "lbs. of ethyl acetate. To this solution was added 13 lbs. of butyraldehyde and a solution of 2 lbs. of sulfuric acid in 2 lbs. of water. The reaction mixture was allowed to stand for 8 days at 40 C., after which it was diluted with acetone, and the resin precipitated by pouring into cold water, washed and dried. Analysis showed the resin to have an acetate group content equivalent to' 7.8% by weight of polyvinyl acetate and a hydroxyl group content equivalentto 4.8% by weight of polyvinyl alcohol.

An example of the preparation of a polyvinyl content equivbutyraldehyde acetaldehyde mixed acetal resin is given in French Patent 813,303, Example 2.

What I claim as my invention and desire to be secured by Letters Patent of the United States is:

1. A composition of matter comprising a polyvinyl acetal resin and diethylene glycol ditetra hydrofuroate as a plasticizer therefor. i

2. A transparent, flexible sheet comprising 100 parts of a polyvinyl acetal resin and 5 to parts, approximately, of diethylene glycol ditetrahydrofuroate as a plasticizer therefor.

Q 3. A transparent, rubbery sheet comprising 100 parts of a polyvinyl acetal resin in which a pre dominating proportion of the acetal groups are butyraldehyde acetal groups, and at least 40 parts, approximately, of diethylene glycol ditetrahydrofuroate as an elasticizer therefor.

4. A composition of matter comprising a polyvinyl acetaldehydeacetal resin and diethylene glycol ditetrahydrofuroate as a plasticizer. there- ,tor.

5. A transparent, flexible sheet comprising parts of a polyvinyl acetaidehyde acetal resin and from 5 to 25 parts, approximately,'of diethylene glycol ditetrahydroturoate as a plasticizer therefor.

6. A composition of matter comprising a polyvinyl formaldehyde acetal resin and di'ethylene for.

from 5 to 25 parts, approximately, of diethylene glycol ditetrahydrofuroate as a plasticizer there 8. A composition of matter comprising a polyvinyl butyraldehyde acetal resin and diethylene glycol ditetrahydrofuroate as a plasticizer therefor.

9. A transparent, rubbery sheet comprisinglOO parts of a polyvinyl butyfaldehyde acetal resin and at least 40 parts, approximately, of diethylene glycol ditetrahydroiuroate as an elasticizer therefor.

HENRY ,B. SMITH. 

